package algorithms.solution617;

/**
 * @author 肖皓星
 * @email xiaohaoxing@outlook.com
 */
public class Solution {
    public TreeNode mergeTrees(TreeNode t1, TreeNode t2) {
        if(t1 == null && t2 == null) {
            return null;
        }
        if(t1 == null) {
            return t2;
        }
        if(t2 == null) {
            return t1;
        }
        TreeNode node = new TreeNode(t1.val + t2.val);
        node.left = mergeTrees(t1.left, t2.left);
        node.right = mergeTrees(t1.right, t2.right);
        return node;
    }
}

class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
    
    TreeNode(int x) {
        val = x;
    }
}